Impeller wheel

ABSTRACT

An impeller wheel has at least one lateral disk and an impeller cage connected centrally on a first face of the lateral disk. Blasting material to be distributed with the impeller wheel is introduced in an axial feeding direction into a central area of the impeller cage. Radial blades are connected to the first face of the lateral disk. Guide blades are connected to the first face of the lateral disk and positioned between the radial blades. The radial blades have radially inner ends spaced at a first distance from a center of the lateral disk and the guide blades have radially inner ends spaced at a second distance from the center of the lateral disk. The second distance is greater than the first distance. The impeller cage is embodied as an auxiliary impeller wheel having auxiliary blades. The auxiliary blades have a greater axial length than the radial blades.

BACKGROUND OF THE INVENTION

The invention relates to an impeller wheel with radially extendingblades which are connected to at least one lateral disc and whose innerends are spaced at a distance to the center, further including animpeller cage with unloading openings arranged in the central area ofthe lateral disc which rotates together with the impeller wheel and inwhose central area the blasting medium to be accelerated is introducedin the axial direction.

SUMMARY OF THE INVENTION

With devices furnished with such impeller wheels, which devices are, forexample, known from German Offenlegungsschrift 25 38 228, surfaces ofmetallic rolled products are freed of scales and/or rust before aprotective coating is applied to the surface, whereby against thesurface a blasting medium is blasted which is comprised of fine metalparticles. In such an impeller wheel all particles of the blastingmedium, upon exiting the impeller wheel, move outwardly radially andsubstantially parallel to the blades. A considerable number of theseparticles impinges on the lateral discs and the blades and reboundstherefrom like a pingpong ball. This is not only negative with regard tothe exit velocity of the blasting medium from the impeller wheel, butalso results in a non-uniform distribution of the blasting medium on thesurface to be cleaned. The impact of the blasting medium particles ontothe parts of the impeller wheel results in considerable wear.

The impeller wheel according to the present invention is primarilycharacterized by:

at least one lateral disk;

an impeller cage connected centrally on a first face of the lateraldisk, wherein a blasting material to be distributed with the impellerwheel is introduced in an axial feeding direction into a central area ofthe impeller cage;

radial blades connected to the first face of the lateral disk;

guide blades connected to the first face of the lateral disk andpositioned between the radial blades;

the radial blades having radially inner ends spaced at a first distancefrom a center of the lateral disk and the guide blades having radiallyinner ends spaced at a second distance from the center of the lateraldisk;

the second distance being greater than the first distance;

the impeller cage embodied as an auxiliary impeller wheel comprisingauxiliary blades;

the auxiliary blades having a greater axial length than the radialblades.

The auxiliary blades have free ends remote from the lateral disk and thefree ends taper in a direction counter to the feeding direction of theblasting material.

The impeller wheel may further comprise a funnel-shaped sleeve arrangedin the vicinity of the free ends and widening in the feeding direction.

The lateral disk has a second face opposite the first face, and thesecond face has ribs.

The impeller wheel is preferably embodied as a welded construction.

The auxiliary impeller is expediently driven independently of theimpeller wheel.

It is an object of the invention to reduce the wear of the impellerwheel resulting from the blasting medium and to simultaneously generatea blasting pattern having uniform coverage over the entire exit angle ofthe blasting medium from the impeller wheel and having approximatelyparallel lateral borders.

This object is inventively solved based on an impeller wheel of theaforementioned kind such that between the blades of the impeller wheelguide blades are arranged the inner ends of which have a greaterdistance to the center of the impeller wheel than those of the bladesand the impeller cage is embodied as an auxiliary impeller wheel. Theaxial length of the blades of the auxiliary impeller wheel is greaterthan that of the blades of the impeller wheel by a considerable amount.

Due to the inventive embodiment of the impeller cage as an auxiliaryimpeller wheel the introduced blasting medium, before entering theimpeller wheel, already moves on a circular path so that the blastingmedium which exits the auxiliary impeller wheel, enters on a spiralcircumferential path the impeller wheel so that the impact of blastingmedium onto the blades of the impeller wheel is substantially prevented.For improving the spiral movement of the blasting medium along its paththrough the impeller wheel, the guide blades participate in that theycatch stray blasting medium and channel it so that a uniformdistribution of the blasting medium onto the surface to be treated isachieved. In a preferred embodiment of the invention the blades of theauxiliary impeller wheel taper in the direction of the inlet end sothat, upon rotation of the impeller wheel, they form, in the directionof flow of the blasting medium, a conically tapering hollow space viawhich the blasting medium, for increasing the throughput, can optimallyenter the blade area of the auxiliary impeller wheel. In this context ithas been especially advantageous to arrange at the free ends of theblades of the auxiliary impeller wheel a truncated cone-shaped sleevethat widens in the flow direction of the blasting medium. This sleevecan also be formed by a corresponding funnel-shaped widened portion ofthe outlet end of the inlet tube for the blasting medium to a blastingdevice.

In another expedient embodiment of the invention, ribs are provided atthe outer surface or surfaces of the lateral disc or discs of theimpeller wheel. With these ribs the blasting medium entering the spacebetween the impeller wheel and the housing thereof is radially outwardlyguided so that a seal between the housing and the drive shaft of theimpeller wheel is obsolete.

Due to the reduced wear resulting from the inventive measures, theimpeller wheel can be embodied as a welded construction with straight orcurved blades, which results in a considerable weight reduction.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention will be explained with the aid of thedrawings. It is represented in:

FIG. 1 a schematic sectional view of the inventive impeller wheel whichis arranged in a housing;

FIG. 2 a schematic sectional view of the impeller wheel and housingalong the line I--I of FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS

The represented impeller wheel 1 is surrounded by housing 2 in whosecentral area an inlet tube 3 opens with which the blasting medium, suchas quartz sand or small steel particles, is fed into the impellerwheel 1. Opposite the opening of the inlet tube 3 the drive shaft 4 ofthe impeller wheel 1 projects from the housing 2.

The impeller wheel 1 comprises a lateral disc 5 which is fastened to thedrive shaft 4 and, at the surface opposite the drive shaft 4, has radialblades 6 the inner ends of which border a distribution sleeve 7 with adistribution opening 8. Between the blades 6 guide blades 9 are securedat the lateral disc 5 the inner ends of which, in contrast to the innerends of the blades 6 are spaced at a distance to the distribution sleeve7. Within the distribution sleeve 7 an auxiliary impeller wheel 10 isembodied which is rotationally fixedly connected to the drive shaft 4,respectively, the lateral disc 5. The axial length of the auxiliaryblades 11 of the auxiliary impeller wheel 10 is greater than that of theblades 6 and the guide blades 9 of the impeller wheel 1 by aconsiderable amount. The free ends of the blades 11 of the auxiliaryimpeller wheel 10 taper in the direction to the inlet end for theblasting medium, respectively, the inlet tube 3 in an arrow-shapedfashion so that in the interior of the rotating auxiliary impeller wheel10 a conical or cup-shaped hollow space 12 is produced extending in thedirection toward the lateral disc 5 via which the blasting medium entersthe auxiliary impeller wheel 10. The tapering free ends of the blades 11of the auxiliary impeller wheel 10 project into the funnel-shapedwidening end 13 of the inlet tube 3 that matches the blade shape.

On the face of the lateral disc 5 opposite the blades 6 ribs 14 areprovided.

The invention is not limited to the represented and disclosedembodiment. It includes variations obvious to a person skilled in theart. For example, at the impeller wheel between the individual blades 6more than a respective single guide blade 9 may be provided. The guideblades 9 may have the same radial length as the blades 6 and thereforeproject past the outer ends of the blades 6.

The present invention is, of course, in no way restricted to thespecific disclosure of the specification and drawings, but alsoencompasses any modifications within the scope of the appended claims.

What I claim is:
 1. An impeller wheel comprising:at least one lateraldisk; an impeller cage connected centrally on a first face of saidlateral disk, wherein a blasting material to be distributed with saidimpeller wheel is introduced in an axial feeding direction into acentral area of said impeller cage; radial blades connected to saidfirst face of said lateral disk; guide blades connected to said firstface of said lateral disk and positioned between said radial blades;said radial blades having radially inner ends spaced at a first distancefrom a center of said lateral disk and said guide blades having radiallyinner ends spaced at a second distance from said center of said lateraldisk; said second distance being greater than said first distance; saidimpeller cage embodied as an auxiliary impeller wheel comprisingauxiliary blades; said auxiliary blades having a greater axial lengththan said radial blades.
 2. An impeller wheel according to claim 1,wherein said auxiliary blades have free ends remote from said lateraldisk and wherein said free ends taper in a direction counter to saidfeeding direction of the blasting material.
 3. An impeller wheelaccording to claim 2, further comprising a funnel-shaped sleeve arrangedin the vicinity of said free ends and widening in said feedingdirection.
 4. An impeller wheel according to claim 1, wherein saidlateral disk has a second face opposite said first face and wherein saidsecond face has ribs.
 5. An impeller wheel according to claim 1,embodied as a welded construction.
 6. An impeller according to claim 1,wherein said auxiliary impeller is driven independently of said impellerwheel.